Method of controlling the transverse basis weight of a paper web using mltiple individually adjustable flow channels and apparatus thereof

ABSTRACT

FLEXIBLE HOSES ARRANGED IN PARALLEL IN A PAPER STOCK FLOW SYSTEM THAT SUPPLIES PAPER STOCK TO A PAPER-FORMING ELEMENT OF A PAPER-FORMING MACHINE OF WHICH THE STOCK IS FORMED INTO A PAPER WEB ARE PROVIDED WITH CLAMPS. THE CLAMPS ARE ADJUSTED TO ALTER THE RELATIVE IMPEDANCES OF THE HOSES SO AS TO MINIMIZE THE TRANSVERSE BASIS WEIGHT VARIATION OF THE PAPER WEB IN RESPONSE TO TRANSVERSE BASIS WEIGHT MEASUREMENTS ACROSS THE WIDTH OF THE PAPER WEB.

March 14, 1972 F. R. BLISS, JR 3,649,445

METHOD OF CONTROLLING THE TRANSVERSE BASIS WEIGHT OF A PAPER WEB USING MULTIPLE INDIVIDUALLY ADJUSTABLE FLOW CHANNELS, AND APPARATUS THEREOF Filed March 14, 1969 3 Sheets-Sheet 1 INVENTOR. FREDERICK R. BLISS, JR.

BY W71, QM, MM

hls ATTORNEYS March 14, 1972 uss, JR 3,649,445

METHOD OF CONTROLLING THE TRANSVERSE BASIS WEIGHT OF A PAPER,

WEB USING MULTIPLE INDIVIDUALLY ADJUSTABLE FLOW CHANNELS. AND APPARATUS THEREOF Filed March 14, 1969 3 Sheets-Sheet 2 I "-J-' L I"'.1ZIE L "i' ',','1 i'j'j.'"

I; I LI I I; W I

Hl- W I h l I! H 1 1| I INVEN'TUR. I? FREDERICK R BLISS, JR.

his A T'TORNEYS March 14, 1972 F. R. BLISS, JR 3,649,445

METHOD OF CONTROLLING THE TRANSVERSE BASIS WEIGHT OF A PAFER v WEB USING MULTIPLE INDIVIDUALLY ADJUSTABLE FLOW CHANNELS, AND APPARATUS THEREOF Filed March 14, 1969 3 Sheets-Sheet 5 FREDERICK R. BLlSS, JR.

MS ATTORNEYS.

nited States Patent O m 3,649,445 METHOD OF CONTROLLING THE TRANSVERSE BASIS WEIGHT OF A PAPER WEB USING MULTI- PLE INDIVIDUALLY ADJUSTABLE FLOW CHAN- NELS, AND APPARATUS THEREOF Frederick R. Bliss, Jr., West Redding, Conn., assignor to Time, Incorporated, New York, N.Y. Filed Mar. 14, 1969, Ser. No. 807,208 Int. Cl. D21f 1/ 06' US. Cl. 162212 3 Claims ABSTRACT OF THE DISCLOSURE Flexible hoses arranged in parallel in a paper stock flow system that supplies paper stock to a paper-forming element of a paper-forming machine on which the stock is formed into a paper web are provided with clamps. The clamps are adjusted to alter the relative impedances of the hoses so as to minimize the transverse basis weight variation of the paper web in response to transverse basis weight measurements across the width of the paper web.

BACKGROUND OF THE INVENTION This invention relates to paper-making flow systems, and, more particularly, to novel and highly effective methods and apparatus whereby the transverse basis weight variation of a paper web formed from stock supplied by the flow system can be minimized.

Conventional methods and apparatus facilitating the formation of a web of paper involve a flow system by which a paper stock is delivered to a paper-making machine. It has long been accepted by skilled paper makers that a high degree of uniformity of stock flow across the width of the flow system must be realized if a paper web having a uniform basis weight across its width is to be obtained. The problems of fluid-flow dynamics are so complex, however, that the best efforts of paper makers heretofore have fallen short of providing to a paper-making machine a sheet of stock that is perfectly uniform from one edge to the other. Inevitably, the concentration of stock fibers at certain portions of the resulting web is greater than that at other (transversely spaced) portions, so that samples of paper taken from different transverse portions of the web are of different quality.

It is necessary to minimize the transverse basis weight variation of the paper web to the extent possible. This desideratum is most urgently felt in the production of highquality paper for use, for example, in magazines and books.

SUMMARY OF THE INVENTION An object of the present invention is to remedy the inability of the best flow systems heretofore known to provide to a paper-making machine a sheet of stock adapted to produce a paper web of uniform characteristics in a transverse direction. A related object of the invention is to facilitate the production of a paper web wherein the transverse basis weight variation is minimal.

The foregoing and other objects of the invention are attained in a system wherein paper stock is discharged from a slice and onto a paper-forming element of a papermaking machine, the stock being supplied to the Slice through a flow system including a plurality of hoses arranged in parallel, the hoses preferably being flexible and generally corresponding respectively to different transversely spaced portions of the paper web formed by the paper-forming machine. In accordance with the invention, the hoses are clamped or otherwise modified to increase the impedance theerof, and the transverse basis-weight variation of the paper web formed by the paper-forming 3,649,445 Patented Mar. 14, 1972 to portions of the web of low basis-weight are relatively increased.

BRIEF DESCRIPTION OF THE DRAWINGS An understanding of additional aspects of the invention can be gainedfrom a consideration of the following detailed description of a representative embodiment thereof, in con unction with the accompanying figures of the drawing, wherein:

FIG. 1 is a side elevation of a representative embodiment of apparatus constructed in accordance with the invention;

FIG. 2 is an end elevation of a portion of the apparatus of FIG. 1;

FIG. 3 is a bottom plan view of a portion of the apparatus of FIGS. 1 and 2;

FIG. 4 is a sectional view taken generally along the line 44 of FIG. 2 and looking in the direction of the arrows; and

. FIG. is a perspective view of one type of flow system 1n combination with which the present invention has particular utility.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIGS. 1-4 show apparatus 10 constructed in accordance with the invention. FIG. 1 is described above as being a side elevation, and FIGS. 2-4 are described consistently with FIG. 1. Actually, the orientation of the apparatus 10 is not critical, it being adapted for use in any flow system having a plurality of separate flow channels in parallel, whether the flow at the point of application of the apparatus 10 is horizontal, straight up, straight down, or inclined up or down at some angle between the horizontal and the vertical.

The apparatus 10 facilitates control of the transverse basis welgh-t of a paper web when used in combination with apparatus of the type shown, for example, in FIG. 5.

FIG. 5 is a schematic perspective view of a flow system 11 of the type shown and claimed in an application of Means et al., Ser. No. 702,101, filed Jan. 31, 1968, for Flow System, assigned to the assignee of the present application. The structure of FIG. 5 is not claimed in the present application but is illustrated and described in order to make clear the operation of the present invention. FIG. 5 shows a side-entering header 12 for delivering stock to the flow system 11. The header 12 includes an inlet designated by an arrow 14, a recirculation exit designated by an arrow 16, and a plurality of flow paths designated by arrows 18 through a plurality of tubes 20.

A flow of stock generated by a pump or other means (not shown) is continuously delivered to the inlet 14. A portion of the stock fiows along paths 18 through the tubes 20 and to the flow system 11, and another portion of the stock is recirculated through the exit 16. Any other suitable means for delivering stock to the flow system 11 may of course be employed The stock following the paths 18 emanates from the tubes 20 into a fiat distribution channel 22 along paths indicated by arrows 24. The distribution channel 22 comprises a lower portion 26 and an upper portion 28. Both portions 26 and 28 of the distribution channel 22 provide flat and unobstructed flow channels for the stock.

Stock flows through the upper fiat channel 28 in the direction indicated by an arrow 30, and the downstream end 32 of the flat channel 28 is connected to the upstream ends 34 of a plurality of flexible hoses 36. (For the sake of clarity, some of the flexible hoses 36 are omitted from the drawing.)

The downstream ends 38 of the flexible hoses 36 are respectively connected to the upstream ends 40 of a plurality of expansion pipes 42. The expansion pipes 42 are arranged in transverse row (with respect to the machine direction or stock-flow direction) corresponding to the transverse row in which the parallel hoses 36 are arranged.

The downstream ends 44 of the expansion pipes 42 are connected to the upstream ends 46 of pipes 48 of changing cross section. The pipes 48 of changing cross sections are also disposed in a transverse row and each is connected to a separate pipe 42. The pipes 48 of changing cross section change gradually along their length from a circular cross section 50 to a rectangular cross section 52.

The downstream ends 54 of the pipes 48 of changing cross section are connected to the upstream end 56 of a second flat channel 58. The stock flows through the flexible hoses 36, the expansion pipes 42, the pipes 48 of changing cross section, and the second flat channel 58, in a direction generally indicated by arrows 60 and 62.

The downstream end 64 of the second flat channel 58 is connected to the upstream end 66 of a nozzle or slice 68. A jet 70 of stock issues from the nozzle 68 and is deposited on an endless permeable band or between two such bands of the wet end of a paper machine (not shown) for formation of a web of paper. The wet end of the paper machine transports the inchoate paper web in a direction generally by an arrow 72.

The apparatus 10 of the present invention improves the apparatus 11 shown in FIG. and all similar apparatus wherein there are parallel flow paths, such as the flow paths provided by the hoses 36. As shown in FIG. 1, the apparatus clamps hoses 36 corresponding generally to the hoses 36 to vary the impedance thereof (it is within the scope of the invention to clamp the hoses at a point where the stock flow is up, down, or horizontal). More particularly, the hoses, which respectively constitute separate flow channels, are initially clamped to increase the impedance thereof, and the transverse basis' weight variation of the paper web formed by the paperforming machine with the hoses so clamped is determined. Techniques for measuring basis weight and determining basis-weight variation across the width of a paper web are conventional and well known to those skilled in the art and so are not described here.

On the basis of this information, a relative adjustment in the clamping is made to alter the relative impedances of the hoses so as to minimize the transverse basis-weight variation of the paper web. Surprisingly, the required adjustment is a reduction in the impedances of hoses corresponding to portions of the web of high basis weight and an increase of the impedances of hoses corresponding to portions of the web of low basis weight. This relationship holds true in cases where an identical or nearly identical adjustment is made to but a few adjacent hoses out of many that are employed in the flow system. For example, such an adjustment is appropriate in cases where five adjacent hoses out of a total of eighty or ninety must be adjusted to correct for a departure from a desired basis weight extending over some 6% of the width of the web. On the other hand, where the departure from the standard or desired basis weight extends over a large fraction of the width of the web, say or more, correction can be made by conventional techniques, such as warping of the slice.

The apparatus 10 can include any means for varying the impedance of the hoses but conveniently includes clamps 80 secured to a frame 82 by bolts 84. A cross member 86 secures the upper ends of the bolts 84 together and is mounted in a stationary manner at the upper ends of the bolts 84.

A movable clamping member 88 having an upper portion 90 of rectangular cross-section (FIG. 4) and a lower portion 92 of semi-circular cross-section secured thereto by screws 94 (FIG. 3) can be raised and lowered by means of a screw 96 having a hexagonal head 98 by means of which the screw 96 can be turned.

The screw 96 is received in a threaded aperture 100 in the stationary cross-member 86 and, when the screw 96 is turned, it moves up and down, carrying with it the movable member 88, in which it is journallecl by a journal 102.

In this manner, the movable member 88 can be brought from the position shown in FIG. 3 to the position shown in FIG. 1, thereby mashing or depressing the flexible hose 36 to reduce the cross-sectional area of the hose at the location of the clamp and increase the impedance of the hose. Positioning notches 104 shown in FIG. 2 facilitate recording of the positions of the screw heads 98 when the machine is properly adjusted and return to such positions on start-up or following an upset. Lock nuts 106 facilitate locking the screws 96 in their desired positions to prevent accidental turning thereof.

The hoses 36' are accurately positioned on the frame 82 by U-clamps 108 so that they are not accidentally dislodged by vibrations, pulsations, or machine attendants. The frame 82 is mounted rigidly in cantilever fashion on supporting structure 108 and 110, as shown in FIG. 1. As shown in FIG. 2, the clamps 80 are mounted generally transversely of the hoses 36 but in staggered relation in view of space requirements. Similarly, the U- brackets 108 are mounted generally transversely of the hoses 36 but in staggered relation.

Thus there is provided in accordance with the invention novel and highly effective methods and apparatus facilitating the production of a web of paper of substantially uniform basis weight across the width thereof. Many modifications in form and detail of the representative embodiment disclosed herein will readily occur to those skilled in the art. For example, valves or other means besides clamps may be employed to vary the impedance of the hoses. In such case, the hoses need not be flexible. Accordingly, the invention is to be construed as including all of the embodiments thereof within the scope of the appended claims.

I claim:

1. A method of controlling and substantially eliminating variations in the transverse basis weight of a paper web formed by the discharge of a paper stock from a slice onto a paper-forming element of a paper-making machine, said paper stock being supplied to said slice through a flow system including a plurality of separate, individually adjustable flow channels arranged in parallel upstream of said slice, said flow channels generally corresponding respectively to different portions of the paper web formed by the paper-forming machine, comprising the steps of modifying said flow channels at points upstream of and in spaced-apart relation to said slice to increase the impedances thereof, determining the transverse basis weight variation of the paper web formed by the paper-forming machine with the flow channels so modified, and further modifying said flow channels at said points to alter the relative impedances of said flow channels so as to minimize variations in the transverse basis weight of said paper web.

2. A method of controlling and substantially eliminat ing variations in the transverse basis weight of a paper web formed by the discharge of a paper stock from a slice onto a paper-forming element of a paper-making machine, said paper stock being supplied to said slice through a flow system including a plurality of separate, individually adjustable flow channels arranged in parallel, said flow channels generally corresponding respectively to different portions of the paper web formed by the paperrnaking machine, comprising the steps of modifying said flow channels at points upstream of and in spaced-apart relation to said slice to increase the impedances thereof, determining the transverse basis weight variation of the paper web formed by the paper-forming machine with the flow channels so modified, and further modifying said flow channels at said points by relatively reducing the impedances of flow channels corresponding to portions of said web of high basis weight and relatively increasing the impedances of fiow channels corresponding to portions of said web of low basis weight so as to minimize variations in the transverse basis weight of said paper web.

3. In a flow system for supplying a paper stock to a slice from which said stock is discharged onto a paperforming element of a paper-forming machine and formed into a paper web, said flow system including a plurality of flexible hoses arranged in parallel through which said stock flows en route to said slice, the improvement comprising clamping means for clamping said hoses to re- 6 strict the cross-sectional fiow areas of said hoses, and adjusting means for adjusting said clamping means to alter said cross-sectional flow areas, whereby the trans verse basis weight variation of said paper web can be minimized.

References Cited UNITED STATES PATENTS 2,922,475 1/ 1960 Alexander l6'2252 3,345,254 10/1967 Kilian 16 2343 3,486,972 12/1969 Nagell 162343 3,413,192 11/1968 Beecher 162259 REUBEN FRIEDMAN, Primary Examiner 15 R. H. ANDERSON, Assistant Examiner U.S. C1. X.R. 162259, 343 

